Illustrative impact based on published industry benchmarks — not results from a specific client.
Average cost of one hour of downtime, mid-size/large enterprises
Large enterprises reporting $1M-5M+ per hour of downtime
Orgs requiring 99.99%+ ("five nines or near") uptime (ITIC reliability survey)
The challenge
A regional fintech ran core transaction processing on a single availability zone with no automated failover, exposing the business to the downtime costs ITIC's industry-wide survey finds are now the norm for enterprises this size.
Our approach
We re-architect the workload across multiple availability zones with automated failover — health-checked DNS routing plus multi-AZ database replication — add chaos-engineering drills, and instrument full-stack observability with alerting tied to real error budgets.
Expected impact
ITIC's 2024 downtime survey found the average cost of a single hour of downtime now tops $300,000 for over 90% of mid-size and large enterprises, with 41% reporting $1M-5M+ per hour — the exposure this re-architecture is built to close.
ITIC's Hourly Cost of Downtime Survey — one of the longest-running studies of its kind, polling over 1,000 firms — found the average cost of a single hour of downtime now exceeds $300,000 for more than 90% of mid-size and large enterprises, with 41% of large enterprises reporting $1M-5M+ per hour for the highest-stakes verticals like banking and transaction processing.
What a single-AZ failure actually costs
A single availability zone going down doesn't sound dramatic until it takes the whole transaction-processing system with it — no automated failover means every minute of the outage is billed at the full downtime-cost rate ITIC's survey documents, with no path to recovery except a manual, high-stress scramble.
The re-architecture, layer by layer
We re-architect the workload across multiple availability zones with automated failover — health-checked DNS routing plus multi-AZ database replication — add chaos-engineering drills, and instrument full-stack observability with alerting tied to real error budgets. The diagram below shows how the pieces fit together.
Multi-AZ high-availability architecture
Automated failover across availability zones — a blueprint of standard components, not a live deployment
Tap any component above for its role and the real tech.
A blueprint of standard multi-AZ components — adapted to whatever compute/database you already run, not a fixed template.
- Route 53 (API, Health-checked DNS failover): Routes traffic away from an unhealthy AZ automatically, no manual DNS change needed.
- EKS — AZ-A (Service, Kubernetes, pod disruption budgets): Primary compute, spread across nodes in this zone.
- EKS — AZ-B (Service, Kubernetes, pod disruption budgets): Standby capacity in a second zone, absorbing traffic on failover.
- Aurora (multi-AZ) (Data, Synchronous replication): Database replicates synchronously across zones so a failover loses no committed data.
- Redis cache (Data, Multi-AZ replication group): Session/cache layer, replicated so a zone failure doesn't cold-start the cache.
- Datadog + PagerDuty (Service, SLO-based alerting): Pages on error-budget burn, not on every noisy metric spike.
This pairs naturally with the delivery-pipeline discipline in our CI/CD modernization blueprint — a fast, safe deployment pipeline and a resilient runtime architecture solve different halves of the same reliability problem.
Built with
Frequently asked
- Is $300K/hour a realistic downtime cost, or an outlier?
- ITIC's 2024 Hourly Cost of Downtime Survey — polling over 1,000 firms worldwide — found this is the average for over 90% of mid-size and large enterprises, not an outlier case. Costs concentrate even higher for banking, healthcare, and transaction-processing verticals specifically.
- Does multi-AZ mean multi-region too?
- Not necessarily — multi-AZ (spreading across data centers within one region) handles most availability failures at much lower cost and complexity than multi-region. We'd only recommend multi-region if the risk profile (e.g. an entire region going down) genuinely justifies the added cost.
- How do you know the failover actually works before a real incident?
- Chaos-engineering drills — deliberately triggering failures in a controlled way — verify the failover path under realistic conditions, rather than trusting it works because it looks correct on a architecture diagram.
➜ ~ ready to ship
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